1. Field of the Invention
This invention relates to a paper machine mesh, in particular a forming mesh.
2. Description of the Related Art
Forming meshes are used in the forming section of a paper machine. During the forming process, a fiber suspension from the headbox of the paper machine is applied to one forming mesh or to two forming meshes (in the case of gap formers). It is an object of the forming mesh in this case to dewater the fiber suspension and to form a fibrous web, whereby as little cellulose fiber and filler material as possible should be separated from the fiber suspension during the dewatering process.
The quality of the formed fibrous web is co-defined in this case to a great extent by the structure of the surface of the forming mesh facing the fibrous web (paper side). The life of the forming mesh, on the other hand, is greatly influenced by the structure of the surface of the forming mesh facing the paper machine (machine side).
To be able to take account of these in part contradictory requirements, multilayer paper machine meshes with a paper-side fabric layer and a machine-side fabric layer were developed, whereby the two fabric layers are connected to each other by so-called binders. To guarantee as uniform a paper-side fabric structure as possible, the binder threads are preferably an integral component of the paper-side weaving structure (integral binder threads), as the result of which a tendency to marking due to the tying of the binder threads is reduced.
On the weft-tied paper machine meshes with integral interchanging binder threads known from the prior art, the binder threads weave alternately with warp threads of the upper and the lower fabric layer, whereby each binder thread is woven as a rule with several upper warp threads before said binder thread crosses a single lower warp thread on the outer side of the lower fabric layer in order to form a tie-on point and subsequently to weave again with several upper warp threads.
The known meshes of said kind have the disadvantage that the lower fabric layer is tied at each tie-on point only by way of one warp thread to the upper fabric layer, as the result of which a high force acts on said warp thread and pulls it into the inside of the mesh, thus exerting a negative effect on the flatness of the mesh.
Furthermore, the binder threads on the known meshes of said kind often cover a large distance between the upper and the lower fabric layer, as the result of which the meshes known from the prior art are often very thick and therefore carry a lot of water.
In addition, the meshes known from the prior art often display a dewatering behavior which varies greatly over the mesh surface and can lead to hydraulic marking of the paper formed on such meshes.
Furthermore, on the known meshes the binder threads between the fabric layers are often exposed to high wear because often said threads are not sufficiently fixed between the fabric layers.
What is needed in the art is a paper machine mesh on which the disadvantages previously referred to no longer arise or arise at least to a reduced extent only.